Firearms

ABSTRACT

A barrel assembly comprising a barrel ( 37 ); a plurality of projectiles ( 30 ) axially disposed within the barrel for operative sealing engagement with a bore ( 36 ) of the barrel; and a plurality of discrete propellant charges for propelling each projectile of the plurality of projectiles sequentially through a muzzle of the barrel ( 37 ). Each projectile of the plurality of projectiles includes a tapered anvil portion ( 31 ); a sealing portion ( 35 ) extending about the tapered anvil portion for sealing engagement with the bore ( 36 ) of the barrel ( 37 ) upon the projectile being inserted into the barrel before firing, the sealing portion being forwardly moveable relative to the tapered anvil portion for operative freeing from the tapered anvil portion and for providing a bypass passage between propellant charges. The tapered anvil portion ( 31 ) includes an anvil extension forming a spine ( 33 ) abutting the tapered anvil portion of a trailing projectile of the plurality of projectiles, whereby if the tapered anvil portion of the trailing projectile of the plurality of projectiles has an increased resistance to forward movement, the sealing portion ( 35 ) of the trailing projectile is urged to move forward along the tapered anvil portion by exposure of a rear face ( 38 ) of the sealing portion to respective ones of the plurality of discrete propellant charges for forward propulsion of the sealing portion ( 35 ) relative to the tapered anvil portion ( 31 ).

TECHNICAL FIELD

[0001] The invention relates to munitions and firearms.

[0002] This invention has particular, but not exclusive, applicationproviding operational safety improvements to barrels of the type havinga plurality of projectiles stacked axially within the barrel in sealingengagement therewith together with discrete propellant charges which areselectively ignitable for propelling the projectiles sequentiallythrough the muzzle of the barrel and the sealing engagement betweenprojectiles and barrel being such as to prevent rearward travel of theignited propellant charge to trailing propellant charges. Such barrelswill be referred to hereinafter as of the type described.

BACKGROUND ART

[0003] This invention has particular application to munitions andfirearms inventions as described in my earlier International PatentApplications Nos. PCT/AU94/00124 and PCT/AU96/00459 which describe awedging action between the sealing portion and an anvil portion of aprojectile which effects a seal to prevent the products of combustion ofthe propellant charge for a leading projectile leaking to the nextadjacent unfired propellant charge and igniting same.

[0004] During testing of prototypes made according to the abovementionedinventions concern has been raised regarding the possibility of amalfunction occurring such as a misfiring or a “hang fire” or like .While no jamming of projectiles has been experienced it is consideredthat this possibility needs to be minimised. The present system operatesat about 40,000 psi chamber pressure but higher pressures in the orderof 60,000 psi plus may be utilised.

[0005] It is envisaged that a misfire may occur either by a projectilejamming in the barrel or by the propellant for a trailing projectilebeing ignited prior to the propellant associated with a leadingprojectile.

[0006] This invention seeks to eliminate or alleviate misfiring and/orto alleviate any serious consequences in the event of a misfireoccurring.

DISCLOSURE OF INVENTION

[0007] With the foregoing in view, this invention in one aspect residesbroadly in a method of minimising misfiring or alleviating theirconsequences in a barrel of the type described including:

[0008] forming at least each trailing projectile with a sealing portionextending about a tapered anvil portion and moveable therealong forexpansion into sealing engagement with the barrel bore, and

[0009] providing disengagement means for operatively disengaging thesealing portion from the anvil portion in response to ignition of thepropellant charge associated with the projectile.

[0010] The method may be suited only to trailing projectiles to providea forward bypass path for ignited propellant for alleviating the effectof a hang fire. Alternatively the method may be applied to eachprojectile including the leading projectile to enable effectivedischarge of projectiles loaded with high barrel engaging forces.

[0011] In the case of application of the method to trailing projectilesonly, the disengagement means may be constituted by an anvil extensionin the form of a spine placing the trailing anvil in columnarrelationship with the adjacent leading projectile thereby increasing theresistance to forward movement of the trailing anvil portion andenabling the sealing portion to move forward along the anvil portion foroperative disengagement therefrom.

[0012] This disengagement permits products of combustion of the trailingpropellant charge to pass beyond the sealing portion to the leadingpropellant charge so as to ignite same and cause the leading projectileto be fired to free the barrel path for the trailing projectile. Thismay occur as a very quick chain-like reaction causing all projectilesahead of the misfired propellant charge to be discharged.

[0013] For this purpose the sealing portion and the anvil portion of thetrailing projectile or projectiles are of such form that the increasedresistance to movement of a combined leading projectile and trailingprojectile, upon ignition of the trailing projectile's propellantcharge, permits the trailing sealing portion to accelerate more quicklythan the trailing anvil portion to create a bleed passage about orthrough the trailing sealing portion for combustion gases to passtherethrough and ignite the leading propellant charge.

[0014] The extension of the anvil portions may be rear or frontextensions or both, with the extension being in continuous abuttingrelationship throughout the barrel to form a compression resistantcolumn positively locating the respective anvil portions in the barrel.

[0015] Maximum chamber pressure will be reached prior to commencement ofthe bleed past the sealing portion. As a result the sealing portion ofthe trailing projectile will be forced forward until the combustionproducts bleed towards the leading projectile. Because of the slighttime delay that occurs between the ignition of the propellant of thefollowing projectile and the subsequent sympathetic ignition of thepropellant of the leading projectile, it is unlikely that the resultantchamber pressure will exceed a reasonable allowable maximum.

[0016] The result should be that both projectiles will leave the barrelnormally except that the sealing portion of the trailing projectile mayseparate from its anvil. Preferably the sealing portion is in the formof a malleable nose part slidable along a centrally located anvilextension and having a conical cavity extending in from an open rear endand in which the conical shaped anvil portion is located.

[0017] Alternatively in the case of application of the method totrailing projectiles only, the disengagement means may be constituted bya pressure sensitive leverage system connected between the anvil portionand the sealing portion which is normally inoperative so as not toaffect the operation of the projectile but which operates when pressuresin the barrel behind the projectile increases beyond a safe operatingpressure to lever the sealing portion along the anvil portion to adisengaged position.

[0018] The pressure sensitive leverage system may be used withprojectiles having forward or rearward diverging wedge surfaces betweenthe anvil portion and the sealing portion. Suitably the pressuresensitive leverage system includes an actuator mounted on the rear endface of the projectile and preferably it is in the form of a collapsibleplate which normally bears against the end face for firing in abuttingrelationship thereto but which upon being subject to extreme pressuresdistorts to provide movement to actuate the leverage system.

[0019] In the case of application of the method to a leading and/ortrailing projectiles, the disengagement means may be constituted by ahammer member supported for free forward movement into a cavity formedin the exposed rear end of the anvil portion such that the hammer memberis driven forward upon ignition of the associated propellant charge toimpart its energy to the anvil portion by impact so as to jolt the anvilportion from operative sealing engagement with the sealing portion.

[0020] The effect of this will be to assist in instantly freeing theanvil portion to minimise any chance of jamming of the projectilepreviously wedged in the barrel. Furthermore in the case of a trailingprojectile the freeing of the anvil portion from the sealing portionwill provide a bleed passage as previously described for ignition in atrailing projectile to pass forwards and ignite the propellant charge ofa remaining leading projectile.

[0021] It is preferred that the leading or each projectile include atapered sealing portion in the form of a malleable band extending abouta complementary tapered anvil portion such that forward movement of theanvil portion relative to the sealing portion operatively disengages theanvil portion therefrom.

[0022] The hammer member may constitute a major or minor portion of theprojectile either by bulk or weight. Preferably the cavity in which thehammer member is supported is a blind cavity formed such that inoperation, the hammer strikes the end wall of the blind cavity. However,if desired the cavity may extend forwardly through the projectile andvarious forms of obstructions may be used to impede movement of thehammer through the cavity. The obstructions may be a forward narrowingof the cavity or abutments protruding in from the wall of the cavity.

[0023] In one form the hammer is a relatively large diameter cylindricalbody sealably and slidably supported in a correspondingly shaped cavityand moveable to a home or impacted position against the end wall of thecavity and at which the cavity is substantially filled by the hammer.

[0024] The hammer may be formed from the same material as the anvilportion or it may be formed from a different material such as a materialhaving a different density or a different malleability, the particularcombination of physical sizes, configurations and characteristics beingselected to suit the purpose of the projectile.

[0025] In another aspect this invention resides broadly in a barrel ofthe type described, wherein:

[0026] each trailing projectile has a sealing portion extending about atapered anvil portion and arranged in sealing engagement with the barrelbore and moveable forwardly therealong for operative freeing from theanvil portion;

[0027] a spine extends from each anvil portion placing the anvilportions in columnar relationship with the barrel, and

[0028] the rear part of each sealing projectile is exposed to theirrespective propellant charges for forward propulsion relative to theanvil portion about which they extend when forward movement of suchanvil portions is resisted.

[0029] In a further aspect this invention resides broadly in a barrel ofthe type described, wherein:

[0030] each projectile includes a sealing portion extending about atapered anvil portion and loaded into the barrel with high barrelengaging forces by relative forward movement of the sealing portionalong the anvil portion;

[0031] each projectile includes a hammer member supported for freeforward movement into a cavity formed in the exposed rear end of theanvil portion, and

[0032] each hammer member being exposed, in use, to its ignitedpropellant for forward acceleration to impart its energy to the anvilportion by impact so as to jolt the anvil portion from operative sealingengagement with the sealing portion.

[0033] In yet a further aspect this invention resides broadly in abarrel of the type described, wherein:

[0034] each projectile includes a sealing portion extending about atapered anvil portion and loaded into the barrel by relative forwardmovement of the sealing portion along the anvil portion;

[0035] each projectile includes a pressure sensitive leverage systemconnected between the anvil portion and the sealing portion whichoperates when pressures in the barrel behind the projectile increasesbeyond a safe operating pressure to lever the sealing portion rearwardlyalong the anvil portion to a disengaged position.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0036] In order that this invention may be more readily understood andput into practical effect, reference will now be made to theaccompanying drawings which illustrate typical embodiments of theinvention, wherein:

[0037]FIG. 1 is a diagrammatic cut-away view of a typical hammer freedprojectile according to one aspect of this invention;

[0038]FIGS. 2A to 2C diagrammatically illustrate the results of a hangfire in a trailing round, and

[0039]FIGS. 3A and 3B illustrate the sequence of operations of a furtherembodiment of the invention.

[0040] According to the embodiment illustrated in FIG. 1, eachprojectile assembly 10 in a barrel of the type described is supported ina barrel 11 together with propellant in the trailing space 12immediately behind the projectile assembly 10.

[0041] Each projectile assembly 10 includes a generally bullet shapedanvil part 14 having a waisted body portion 15 which tapers inwardlyslightly towards its trailing end. A complementary tapered sealing band16 is supported on the waisted body portion 15. The band has free travelspace at each end of the waisted body portion 15 such that it may moveto and fro to engage and operative disengage therefrom.

[0042] When loading, impact applied to the projectile 14, provided inthe direction ‘A’ when the projectile is located at the appropriatelocation within the barrel 11, will cause the complementary wedgingsurfaces 20 a and 20 b to engage and expand the sealing band 16outwardly into firm sealing engagement with the bore 21 of the barrel11, sealing and locating the projectile assembly 10 in place in thebarrel 11.

[0043] This seal prevents the ignited propellant charge from bypassingthe adjacent trailing projectile and igniting its propellant charge, butpermits the complementary wedging surfaces 20 a and 20 b to disengageupon relative forward movement of the anvil part 14.

[0044] The trailing face 22 of the sealing band 16 is oppositely taperedto its inner face 20 a and at a relatively sharp angle and it is spacedfrom the correspondingly tapered rear return face 23 of the waisted bodyportion 15. When the faces 22 and 23 are operatively engage at thecommencement of forward movement of the anvil part 14 as it is propelledthrough the barrel 11 so as to carry the sealing band 16 with theprojectile through the barrel and in effective sealing engagementtherewith.

[0045] In this embodiment, a relatively large diameter blind cylindricalcavity 25 is provided centrally in the rear face 26 of the projectile 14and a corresponding shaped hammer 27 is slidably engaged within therecess 25. The hammer 27 is substantially the same size as the recess 25so that the recess 25 is filled when the hammer is fully insertedthereto. However, when loaded the hammer 27 is maintained slightly proudof the rear face 26 so that a gap 28 is provided in front of the hammer27 into which it may travel in direction B upon ignition of thepropellant charge in the space 12.

[0046] In this embodiment the hammer 27 is made of a relatively rigidmaterial such as steel and the initial pressure within the barrel 11resulting from ignition of the propellant charge will drive the hammer27 forwardly until it contacts the blind end 29 of the cavity orrecesses 25 providing an impact to free the wedging surfaces 20 a and 20b from one another and thus unlock the projectile assembly 10 from thebarrel 11. Thereafter the pressure within the barrel will act on thecombined rear face of the hammer 27 and the projectile 14 to propel theprojectile assembly 10 from the barrel 11.

[0047] It is considered that the impact or jolting provided by initialmovement of the hammer 27 will ensure that release of the locked wedgingsurfaces 20 a and 20 b will occur instantaneously and ensure effectivepropulsion of the projectile assembly from the barrel.

[0048] It is also considered that this arrangement will be particularlyadvantageous where high in-barrel pressures such as in the order of60,000 psi or more are utilised to propel the projectiles and/or whererelatively large impact forces in the direction ‘A’ are utilised to lockthe projectile assembly 14 in place in the barrel 11.

[0049] In the case of a hang fire in a trailing round the operativerelease of the locked wedging surfaces 20 a and 20 b will permitsufficient bypass of propellant gases to ignite the propellant of theleading round.

[0050] In the embodiment illustrated in FIG. 2 and referring initiallyto FIG. 2A it will be seen that each projectile assembly 30 includes aconical anvil portion 31 formed with axial extension columns 32 and 33extending from the leading and trailing ends thereof. An annular nosepart 34 formed of malleable material extends about the leading columnportion 32 and rearwardly about the anvil portion 31 forming aninternally tapered sealing ring 35 which may be forced outward intosealing engagement with the bore 36 of the barrel 37 by relativerearward movement thereof along the anvil portion 31. This effects anoperative seal as previously described to prevent rearward bypass ofhigh pressure ignited propellant gases. Both the rear end 38 of thesealing ring 35 and the anvil portion 31 are exposed to the propellantcharge.

[0051] It will be seen that the leading and trailing extension columns32 and 33 form a compression resistant column throughout the barrel 37and are of the same diameter so that the annular nose part 34 may moveforward past the column join at 40.

[0052] Under normal circumstances ignition of the leading propellantcharge 41 will dislodge the leading projectile and force it out throughthe muzzle at high velocity. In the event of a hang fire occurring in atrailing round, such as is illustrated in FIGS. 2Ba and 2C, theresistance to forward movement of the trailing anvil portion 31increases as it must also move the leading projectile through theabutting columns 32 and 33.

[0053] A lesser resistance to forward movement of the nose part 34enables it to move forward slightly along the anvil portion 31 so thatpropellant gases will bleed forwardly and ignite the leading propellantcharge 41 causing the both projectiles to be accelerated through themuzzle as described above.

[0054] In the embodiment illustrated in FIG. 3 and referring initiallyto FIG. 3A it will be seen that the sealing arrangement of eachprojectile assembly 50 is of the same form as illustrated in FIG. 1.However in this embodiment a leverage system, illustrateddiagrammatically at 51 extends from a deformable end cap 52 to engage ina recess 53 provide on the inside surface of the sealing band 55. Duringnormal firing the projectile will behave normally and exit the muzzle inthe form illustrated in FIG. 3A.

[0055] In the case of a hang fire the end cap 52 is formed so as tocollapse in the middle as a consequence of the high in-barrel pressurescreated by the hang fire. This distortion of the end cap is relayed tothe periphery of the end cap causing the periphery to curve rearwardly,pulling the levers 51 rearwardly and thus freeing the sealing band 55from the tapered waisted portion 56 to provide a bypass passage 57 forignited propellant as described above.

[0056] It will of course be realised that the above has been given onlyby way of illustrative example of the invention and that all suchmodifications and variations thereto as would be apparent to personsskilled in the art are deemed to fall within the broad scope and ambitof the invention as is defined in the appended claims.

The claims defining the invention are as follows:

1. A method of minimising misfiring or alleviating their consequences ina barrel of the type described including: forming at least each trailingprojectile with a sealing portion extending about a tapered anvilportion and moveable therealong for expansion into sealing engagementwith the barrel bore, and providing disengagement means for operativelydisengaging the sealing portion from the anvil portion in response toignition of the propellant charge associated with the projectile.
 2. Themethod as claimed in claim 1 for minimising the effect of a hang fire,wherein the disengagement means is constituted by an anvil extension inthe form of a spine placing the anvil portion of a trailing projectilein columnar relationship with the anvil portion of the adjacent leadingprojectile to increase the resistance to forward movement of thetrailing anvil portion and enabling the sealing portion to move forwardalong the anvil portion for operative disengagement therefrom.
 3. Themethod as claimed in claim 2, wherein the anvil extension includes acentral front extension column extending to the front of the sealingportion and a central rear extension column extending beyond the sealingportion and defining a propellant space between the adjacent abuttingprojectiles.
 4. The method as claimed in claim 1 for minimising theeffect of a hang fire, wherein the disengagement means is constituted bya pressure sensitive leverage system connected between the anvil portionand the sealing portion which operates when pressures in the barrelbehind the projectile increases beyond a safe operating pressure tolever the sealing portion along the anvil portion to a disengagedposition.
 5. The method as claimed in claim 1 for enabling effectivedischarge of projectiles loaded with high barrel engaging forces,wherein the disengagement means is constituted by a hammer membersupported for free forward movement into a cavity formed in the exposedrear end of the anvil portion such that the hammer member is drivenforward upon ignition of the associated propellant charge to impart itsenergy to the anvil portion by impact so as to jolt the anvil portionfrom operative sealing engagement with the sealing portion.
 6. Themethod as claimed in claim 5, wherein each projectile include a taperedsealing portion in the form of a malleable band extending about acomplementary tapered anvil portion such that forward movement of theanvil portion relative to the sealing portion operatively disengages theanvil portion therefrom.
 7. The method as claimed in claim 5, whereinthe cavity in which the hammer member is supported is a blind cavityformed such that in operation upon ignition of the propellant charge,the hammer strikes the end wall of the blind cavity.
 8. A barrel of thetype described, wherein: each trailing projectile has a sealing portionextending about a tapered anvil portion and arranged in sealingengagement with the barrel bore and moveable forwardly therealong foroperative freeing from the anvil portion; a spine extends from eachanvil portion placing the anvil portions in columnar relationship withthe barrel, and the rear part of each sealing projectile is exposed totheir respective propellant charges for forward propulsion relative tothe anvil portion about which they extend when forward movement of suchanvil portions is resisted.
 9. A barrel of the type described, wherein:each projectile includes a sealing portion extending about a taperedanvil portion and loaded into the barrel with high barrel engagingforces by relative forward movement of the sealing portion along theanvil portion; each projectile includes a hammer member supported forfree forward movement into a cavity formed in the exposed rear end ofthe anvil portion, and each hammer member being exposed, in use, to itsignited propellant for forward acceleration to impart its energy to theanvil portion by impact so as to jolt the anvil portion from operativesealing engagement with the sealing portion.
 10. A barrel as claimed inclaim 9, wherein each projectile includes a tapered sealing portion inthe form of a malleable band extending about a complementary taperedanvil portion, and the cavity in which the hammer member is supported isa blind cavity such that in operation upon ignition of the propellantcharge, the hammer strikes the end wall of the blind cavity.
 11. Abarrel of the type described, wherein: each projectile includes asealing portion extending about a tapered anvil portion and loaded intothe barrel by relative forward movement of the sealing portion along theanvil portion; each projectile includes a pressure sensitive leveragesystem connected between the anvil portion and the sealing portion whichoperates when pressures in the barrel behind the projectile increasesbeyond a safe operating pressure to lever the sealing portion rearwardlyalong the anvil portion to a disengaged position.
 12. A barrel assemblysubstantially as hereinbefore described with reference to either of theaccompanying drawings.